LOS ANGELES (AP) -- A Virginia fish importer has been sentenced to more than five years in prison for selling $15.5 million worth of frozen Vietnamese catfish as flounder and other fish in the United States in a scheme to avoid paying import tariffs.

U.S. District Judge Philip Gutierrez on Monday also ordered Peter Xuong Lam, president of Virginia Star Seafood Corp., to pay $12 million to the government as reimbursement of the tariffs.

A second Virginia-based fish importer, Arthur Yavelberg, president of Silver Seas, was sentenced to probation for his role in the scheme.

U.S. Attorney Thomas P. O'Brien said the men were convicted following a three-week trial in October. Lam, 49, of Fairfax, Va., was found guilty of conspiring to import mislabeled fish in order to avoid federal import tariffs and three counts of dealing in fish that he knew had been imported contrary to law.

Yavelberg, 64, of Reston, Va., was convicted of a misdemeanor conspiracy count, O'Brien said.

Prosecutors said Lam and Yavelberg imported 10 million pounds of catfish that was illegally labeled and sold as fillets of sole, grouper, flounder, snakehead, channa and conger pike.

DNA tests revealed that the frozen fish was in fact Pangasius hypophthalmus, a fish in the catfish family marketed under approved trade names including swai or striped pangasius.

An anti-dumping duty was placed on Pangasius hypophthalmus imports from Vietnam in January 2003 after a petition was filed by U.S. catfish farmers, who alleged that this fish was being imported at less than fair market value.

O'Brien said the convictions are the latest in an ongoing prosecution of a conspiracy to avoid the anti-dumping tariffs on fish.

To date, a dozen individuals and companies have been convicted of criminal charges related to the scheme, O'Brien said.

The organizer of the smuggling conspiracy, Henry Nguyen, remains a fugitive and is believed to be residing in Vietnam, authorities said.